Abstract

For non-intrusive high-resolution diagnosis, far- field optical profilometry is an indispensable technology. Modern interferometric profilers can provide 0.1-nm depth resolution without lateral scanning.¹ But fast imaging is difficult for interferometers because close-loop axial scanning must be employed to enlarge the measurement dynamic range.² In contrast, non-interferometric optical profilometry with nanometer depth resolution such as differential confocal microscopy (DCM) has a larger open-loop dynamic range,³ and can perform dynamic measurement on soft samples such as living cells.⁴ But similar to conventional confocal microscopy, DCM requires lateral scanning to profile the whole surface. High-speed scanning mechanisms for fast image display greatly increase the system complexity and cost. To date, nanometer optical profllometry without using interferometric effects and lateral scanning mechanisms is still very desirable.

© 2002 Optical Society of America